Hopefully, none, as the patient should be medically stabilised before trying to get imaging! There are the "4Hs and 4Ts" to consider: hypoxia, hypovolemia, hypothermia, hyper/hypokalemia (and other salts), toxins, tamponade, tension pneumothorax, thrombus. CXR can show obvious changes in the lungs leading to hypoxia or tension pneumothorax, or other evidence of illness (pneumonia, fluid overload, dramatic cardiac abnormalities).

Presentation

Out of hospital cardiac arrest with immediate CPR (by off-duty medics) and ROSC after 5 cycles. Short history of preceding sharp central chest pain.